He is able to speak English. 他会说英语。
Everyone here is able to type. 这儿的每一个人都会打字。
He will be able to get about in a week or two. 再过一两个星期左右他就能走动了。
He studied hard and was able to pass his examinations. 他学习很努力，所以考试及了格。
be able to 不仅有多种时态形式（通常不用于进行时或与 be going to 连用），而且还可以与某些情态动词连用（通常不与 can 连用），甚至还可以有非谓语形式。如：
Since his accident he hasn’t been able to leave the house. 自出事之后，他一直未能离开家。
You might be able to persuade him. 你也许能够说服他。
I hope to be able to do the work. 我希望能干得了这项工作。
I regret not being able to help her. 我很遗憾未能帮助她。